Luckily, converting from TDX to GTFS is not overly difficult, and below are some instructions. This howto is a bit old, as I am only now copying it from my "Notes" folder to put online to help others.
Note: You can now directly download GTFS from the TransportInfo website: https://tdx.131500.com.au
1) Signup for an account with EC2 (AWS), unless you have 16GB of memory available on a machine.
2) Upload TransXChange2GTFS to a place you can download from.
3) Upload the latest TDX data dump from 131500.info to a place you can download from.
4) Login to AWS and start an EC2 instance. I picked a large instance and used 64-bit Ubuntu 10.04, us-east-1 ami-f8f40591
5) Download the Data and transxchange to /mnt
wget http://ec2-175-41-139-176.ap-southeast-1.compute.amazonaws.com/Data20110127.zip wget http://cdn.kelvinism.com/transxchange2GoogleTransit.jar
6) Install Sun JRE.
apt-get install python-software-properties add-apt-repository "deb http://archive.canonical.com/ lucid partner" apt-get update apt-get install sun-java6-jre7) Check how much memory is available
root@domU-12-31-39-10-31-B1:/mnt# free -m total used free shared buffers cached Mem: 7680 626 7053 0 11 329 -/+ buffers/cache: 285 7394 Swap: 0 0 0
8) Create a configuration file sydney.conf
url=http://131500.info timezone=Australia/Sydney default-route-type=2 output-directory=output useagencyshortname=true skipemptyservice=true skiporhpanstops=true
9) If you're on the train like me, start screen, and start converting. The number you pick for "-Xmx" obviously needs to fit in the amount of free memory you have.
java -Xmx104000m -jar dist\transxchange2GoogleTransit.jar Data20120524.zip -c sydney.conf